How much is a 1994 GoldWing worth?

That depends on your location, condition/appearance of the bike and motor/bodywork etc, options, mileage on the odo.,serviced regularly including carb tuning every 5000 miles '94's developes developes flat spots if not !!
The 1994's were no different from the 92's except for standard cb radio and bearings internals and paint colours.All theses contribute to overall pricing.
Generally speaking anywhere from a low of $5000 to a high of $1100 for a low mileage mint unit would be a reasonable expectation.